Mechanized case erectors of one type or another have been on the market for several years. Mechanized case erectors save time in large packaging operations where the high quantity of erected cases needed justifies the typically high expense of such case erectors. Not only are mechanized case erectors expensive to manufacture, they are expensive to operate because they also have special setup, operating and maintenance requirements such as high voltage power, and special servicing of internal systems. They are also large and, thus, require significant floor space. As noted above, the cost of prior art mechanized case erectors, their operational cost and floor space are acceptable by packagers having a constant need for a large number of erected cases.
In the past, the small volume packagers sometimes have been unable to justify the purchase of prior art mechanized case erectors due to the high manufacturing and operational costs associated with such machines. As a result, small volume packagers have usually resorted to erecting cases by hand. Case erection by hand can be expensive. Further, it can lead to medical problems, such as carpal tunnel syndrome, which can lead to workmen's compensation expense.
Several of the above-discussed limitations and many others inherent in prior art mechanized case erectors are apparent from an examination of the patents that have issued on such machines. For example, a complicated wrap-around packaging method is disclosed in U.S. Pat. No. 4,569,182 to Leuvering. Flat blanks are folded and an object is inserted. Minor and major flap folding bars are used (see FIG. 1), as well as vacuum suction cups (see FIG. 3, element 46 and Col. 5, lines 43-50). This is a complicated system designed to deal only with specific needs. The machine is designed to handle a single object of a set size. Adjustments would be difficult and standard blanks are not used.
Another large, complicated and expensive case erector is disclosed in U.S. Pat. No. 4,348,853 to Morse et al. This case erector pulls a blank from a stack and carries it over a long course through bars and along conveyors to prepare it for the insertion of objects therein. The space requirements for this machine may be prohibitive in many environments. Also the machine is not readily adjustable for differing case sizes.
Another apparatus for erecting cases is disclosed in U.S. Pat. No. 4,414,789 to Pattarozzi. Through a complicated means, all flaps are folded at one station before the case is advanced to be strapped. The case erector uses a complicated mechanically synchronized setup including vacuum cups and mechanized flap folders without pneumatic actuators. Large portions of the machine are moved along guide tracks to fold the case flaps. The machine does not easily accommodate cases of different sizes.
U.S. Pat. No. 4,081,945 discloses a conveyor system for erecting cases. Chain and cam-driven pneumatically actuated vacuum cups, pusher bars, and a folder bar are combined along the conveyor system. The machine requires a large area in which to operate since it uses a linear series of steps to fold the case flaps. This machine also is difficult to adjust for different sized cases.
Another packaging system is disclosed in U.S. Pat. No. 3,959,950 to Fukuda. This is also a linearly arranged system with static and moving folder bars. Problems with this system include having to manually open the case, large space requirements, and non-conventional case blanks. As can be seen in FIGS. 1a, 1b, and 2, the bottom minor flaps are each cut into three portions to be able to ride along the conveyor system of the apparatus.
The above-referenced patents illustrate typical limitations and disadvantages of the devices and methods currently in use to erect cases. Besides the specifics discussed in connection with these devices, other limitations such as cost and power requirements also commonly exist. From the above discussion, it should be apparent that an affordable, small, reliable, easy-to-use case erector for use by packagers with smaller quantity applications and/or limited space is not currently available. The present invention was developed to meet this need. As will be understood from the following discussion the present invention provides significant advantages over the prior art devices and methods for erecting cases from blanks for use in containing materials.